A new study reveals that the "Sonic hedgehog" gene plays a similar role in the limb development of both little skate fishes and humans, suggesting that human limbs might have evolved from sharks' gills.

Latest analysis shows that human limbs share a genetic programme with the gills of cartilaginous fishes such as sharks and skates, providing evidence to support a century-old theory on the origin of limbs that had been widely discounted.